One leg swelling, especially if it comes on suddenly
Pain or tenderness in the calf or thigh
Warm skin on the affected leg
Red or discolored skin on the leg
A feeling of tightness or cramping in the leg
Pain that gets worse when standing or walking
Veins near the skin that look more prominent than usual
Shortness of breath, chest pain, or coughing up blood, which can mean the clot has moved to the lungs
Seek urgent medical care if you have these symptoms